T-Mobile's iPhone Is Unique Variant of AT&T's Model

Not exactly accurate

From what I understand, once AT&T exhausts its on-hand stock of the A1428, it will start selling the "new" A1428 that T-Mobile will be selling as well. In other words, Apple will only be producing the "new" A1428 from now on. The new A1428 will be fully compatible with all of AT&T and T-Mobile's GSM, WCDMA and LTE bands.

True, but I wanted to correct a misimpression one may get from the article, which is that the AT&T version will NEVER be compatible with T-Mobile. That statement is true for the A1428 being sold now, but eventually both carriers will supposedly be selling the same A1428 variant, at which point an iPhone 5 sold by AT&T should be fully compatible with T-Mobile.

What I am saying has nothing to do with LTE. I am saying that Apple will be quickly phasing out the current A1428 regardless of carrier and replacing it with a new A1428 variant that will support WCDMA1700 that will be shipped to all carriers currently selling the A1428, not just to T-Mobile.

I understand. Impractical though then. Why put AWS 1700 and 1900 on the same phone if eventually LTE will be the norm?? Just for now? If AT&T would have merged with T-Mobile, then there would have been no worries in that department. So now they have to start tweaking a whole line of phones for interoperability on a network that is going to evolve into one LTE base in the future? Maybe I am missing something here.

I understand. Impractical though then. Why put AWS 1700 and 1900 on the same phone if eventually LTE will be the norm?? Just for now? If AT&T would have merged with T-Mobile, then there would have been no worries in that department. So now they have to start tweaking a whole line of phones for interoperability on a network that is going to evolve into one LTE base in the future? Maybe I am missing something here.

More time than the lifecycle of an iPhone which is a few years. If and when interoperability happens between carriers a LOT has to occur. READ THE ARTICLES. Technology has to produce a small enough radio chip that carries the LTE frequencies. Policy and/or law ...(continues)

The A1428 iPhone 5 variant has always possessed the physical capability for W-CDMA 2100+1700 (i.e. AWS). However, Apple implemented a software lock out to appease AT&T. The software lock out is being removed. Simple as that...